Fuel-fired heat pump system



Sept. 10, 1968 D. D. DENNlS ETAL FUEL-FIRED HEAT PUMP SYSTEM 2Sheets-Sheet 1 Filed March 17, 1967 INVENTORS DAVID D. DENNIS PAUL ESWENSON PAUL F. SWENSON JR. BY W i AT ORNEYS.

Sept. 10, 1968 D. D. DENNIS ETAL 3,400,554

FUEL-FIRED HEAT PUMP SYSTEM Filed March 17, 1967 2 Sheets-Sheet 2 DAVIDD E 533%? PAUL F. SWENSON H62 PAUL F. SWENSON JR.

A ORNE S.

United States Patent 3,400,554 FUEL-FIRED HEAT PUMP SYSTEM David 1).Dennis, Wickliife, Paul F. Swenson, Cleveland Heights, and Paul F.Swenson, Jr., Shaker Heights,

Ohio, assignors to Swenson Research, Inc., South Euclid, Ghio, acorporation of Ghio Filed Mar. 17, 1967, Ser. No. 624,063 5 Claims. (Cl.62-438) ABSTRACT OF THE DISCLOSURE A closed-loop, reversiblehermetically sealed refrigeration cycle the compressor of which isdriven by a vapor turbine supplied with vapor from a once-through typevapor generator of a hermetically sealed closed-loop vapor cycle. Theturbine and compressor are constructed as a unit and are drivinglyinterconnected through a magnetic coupling which is comprised of a pairof spaced but interfitted magnet members which are carried on the endsof the turbine and compressor shafts respectively. A fluid imperviousnon-magnetic barrier or partition member extends between the magnetmembers to seal between the turbine and compressor. A feed pump in theform of an inverted cone is carried on the lower end of the turbineshaft and extends down into a hot well or condensate receiving containerand functions to pump the condensate back to the vapor generator. Thesystem also includes an air duct arrangement which, when the system isoperating on the heating mode, causes the air to be heated by both theFreon cycle and the vapor cycle apparatus. Additionally a vapor by-passline is provided around the turbine to increase the heat available fromthe vapor cycle when needed.

The present invention is directed to the heating and cooling art, and,more particularly, to an improved fuelfired reverse cycle heat pumpsystem.

The invention is particularly applicable for constructing heating andcooling units of a size for use in residential dwellings and will bedescribed with particular reference thereto; however, it is appreciatedthe invention is capable of broader application and could be used forconstructing units for a variety of environmental control applications.

In general, most heat pump systems utilize a prime mover in the form ofan electric motor for driving the compressor of a reversiblefluorocarbon refrigeration cycle. The reason for this is, of course, theconvenience of electricity as the energy source for the prime mover andthe highly desirable characteristics of fluorocarbons as the workingmedium in refrigeration cycles. However, electricity is expensive as anenergy source, especially for the residential user. Based on an energycost per unit refrigeration comparison, the eflicient electric motor isoften not as economical as prime movers using fuels directly. Inaddition, the rotative speeds obtainable from commercially availableelectric motors using normal line power necessitate a reciprocating typecompressor for refrigeration systems of capacity applicable to singleresidences and somewhat larger. Wear, noise and vibration are usuallyattendant to the operation of reciprocating machinery.

The use of a fuel such as gas, fuel oil or coal instead of electricityas the main power source has been considered desirable from thestandpoint of lower energy costs, as well as potentially lower operatingcosts. Generally, previous attempts to design systems using these fuelsas the power source have not been satisfactory.

In general, these fuel burning systems comprise a vapor turbine drivenfluorocarbon compressor. The fuel is 3,400,554 Patented Sept. 10, 1968burned in a vapor generator to heat and vaporize a working fluidnecessary for driving the turbine. Attempts have been made to use bothfluorocarbons and water as the working fluid. However, problemsencountered with both, have prevented the design of an economicallysound system. Attempts to use fluorocarbons as the working fluid havebeen unsatisfactory since fluorocarbons generally have a lowdecomposition temperature and require that the vapor supplied to theturbine be of relatively low temperature. Consequently, the efficiencyof the vapor cycle portion of the system is relatively low. Likewise,attempts to use water as the working fluid have been unsatisfactory.Although ideally, water vapor can yield a much higher cycle efliciencywhen used for driving the turbine, the incompatibility of water andfluorocarbons, and the difiiculty of sealing between the compressor andthe turbine has prevented the use of water as the working fluid. Thosesystems which have attempted to use water have required the use ofcomplicated distillation or liquid separation apparatus such as shown inU.S. patent to Klaben et al. 3,250,082.

Various other problems are also encountered in attempting to designsmall size vapor turbine driven heat pump systems. For example, as iswell known, vapor turbines operate most efficiently under vacuumconditions. After the vapor passes through the turbine and is condensed,a pump functions to return the working fluid to the vapor generator. Insmall units, the static head available is necessarily limited and thepump must pump from a relatively high vacuum. Small capacity pumps whichwill satisfactorily pump from high vacuum conditions are generally notavailable. Consequently, in previous vapor turbine driven heat pumpsystems it has not been economically feasible to operate the turbinesunder high vacuum conditions.

An additional problem present in reverse cycle heat pump systemsgenerally, is their inefficiency when op erating in their heating modeunder high heating requirements.

The present invention provides a fuel-fire reverse cycle heat pumpsystem which overcomes the above problems and permits such systems to beconstructed in small sizes suitable for residential use.

In accordance with one aspect of the present invention a vapor turbinedriven reverse cycle heat pump system is provided which includes: aclosed vapor cycle comprising a vapor generator supplying vapor to avapor turbine, a first heat exchanger for receiving and condensing saidvapor after it has passed through said turbine, and means for returningthe condensed vapor to the vapor generator; a closed circuit reversiblerefrigerant cycle including a compressor drivingly connected to saidturbine and a second heat exchanger and means to selectively cause saidsecond heat exchanger to function as the condenser or evaporator forsaid refrigerant cycle; air duct means interconnecting said first andsecond heat exchangers and means for causing air to flow through saidduct means first over said second heat exchanger and thence over saidfirst heat exchanger when said second heat exchanger is functioning as acondenser for said refrigerant cycle.

The above arrangement serves to greatly increase the overall efficiencyof a vapor turbine driven reverse cycle heat pump system because whenthe system is being used for heating, the available heat in the vaporcycle condenser is used to increase the quantity of usable heat outputof the system.

In accordance with a more limited aspect of the present invention, apump particularly suited for use in a high vacuum environment isprovided which comprises a container means for holding a fluid to bepumped, an elongated member having a longitudinal axis and extendingdownwardly into said container means, said memher having a lower endadapted to be positioned to extend into the fluid in said container andhaving a circular crosssectional configuration as defined by planesperpendicular to said longitudinal axis which gradually increasesupwardly from said lower end, means defining a circumferentiallyextending fluid receiving recess upwardly spaced from said lower end,fluid pick-up means positioned within said recess for receiving fluidreceived therein, and means for rotating said member about itslongitudinal axis.

In accordance with another aspect of the present invention an improvedvapor turbine driven compressor unit is provided which includes: ahousing and partition means dividing said housing into first and secondchambers; a vapor turbine positioned in said first chamber and having anoutput shaft; a compressor positioned in said second chamber and havingan input shaft; said turbine and said compressor being positioned so asto have their respective shafts in general alignment; coupling means fordrivingly interconnecting said shafts in fluid sealed relationship, saidcoupling means comprising a first magnet member positively connected tosaid output shaft and a second magnet member positively connected tosaid input shaft, said first and second magnet members being in spacedmated relationship; and said partition means including a fluidimpervious non-magnetic barrier member positioned between said first andsecond magnet members.

By magnetically interconnecting the turbine and compressor the problemspreviously encountered with regard to sealing are eliminated and theturbine and compressor can operate on incompatible fluids such as waterand Freon.

A primary object of the present invention is the provision of afuel-fire reverse cycle heat pump system.

An additional object of the present invention is the provision of a heatpump system which is highly eflicient and overcomes problems previouslyencountered in heat pump systems.

A further object is the provision of an improved pump especially suitedfor use in a high vacuum environment.

A still further object is the provision of a vapor turbine drivencompressor unit which overcomes problems previously encountered insealing between the turbine and compressor.

Another object is the provision of a magnetic coupling which isespecially suited for use as the driving connection between a compressorand a vapor turbine.

Yet another object is the provision of a turbine driven heat pump systemwhich is especially suited for residential heating and cooling.

These and other objects and advantages will become apparent from thefollowing description when read in conjunction with the accompanyingdrawings wherein:

FIGURE 1 is a somewhat diagrammatic showing of a reversible heat pumpsystem constructed in accordance with the present invention;

FIGURE 2 is a longitudinal cross-sectional view through theturbo-compressor unit of the system;

FIGURE 3 is a cross-sectional view taken on plane 3-3 of FIGURE 2; and

FIGURE 4 is an enlarged view of the feed water or condensate pumpshowing the forces acting on the fluid being pumped.

Referring now to the drawings wherein the showings are for the purposeof illustrating a preferred embodiment of the invention only, and notfor the purpose of limiting same, FIGURE 1 shows the overall arrangementof the system comprising a fuel-fired steam generator unit A, and areversible refrigeration cycle heat pump system B interconnected througha turbo-compressor unit C.

Steam generator A The fuel-fired steam generator unit A is of theoncethrough type and includes an evaporator section and a seriallyconnected superheater section 12. Feedwater is supplied to the unitthrough a line 14 connected with feedwater or condensate pump 16 drivenby the turbine of the turbo-compressor unit C. Steam at a pressure andtemperature dictated by system requirements is conducted from the outletof the superheater 12 by lines 18 and 20 to the turbine 22. The steamtemperature and pressure can be as high as necessary, within the limitof steam power plant practice, to achieve good cycle efliciency.

The steam-generator is fired by a pair of burners 24 and 26 suppliedwith fuel gas through line 28. Burner 24 serves to heat superheatersection 12 of the steam-generator, and is controlled by a conventionaltemperature responsive modulating valve 30 in accordance with thetemperature of the steam leaving the superheater. Burner 26, on theother hand, is utilized to heat the evaporator section 10, and iscontrolled in accordance with the pressure of the steam leaving thesteam-generator by a pressure responsive valve 32. Main gas flow to theburners, and steam flow to the turbine, are controlled by conventionalon-otf solenoid valves 34 and 35 respectively, controlled by a two-steproom thermostat 36. The thermostat is of the type that can be shiftedfrom direct to reverse acting, so as to be capable of controlling thesystem when it is fanctioning in either the heating or cooling mode.

A novel feature of the design of the steam-generator unit A is the meansutilized to prevent damage to the water circuits in the event thatburner operation should be disrupted, such as by lack of fuel, duringcold weather. These means comprise a drain line 38 connected between thelow point of the steam-generator circuitry and a reservoir tank 40. Line38 is controlled by a conventional temperature responsive valve 42 whichis adjusted to open and drain the steam-generator in response totemperature in the range of freezing. As shown in FIGURE 1,

the valve is connected to open in response to low temperatures sensed atthe outlet of the steam-generator. However, it is apparent that otherpoints in the steamgenerator circuitry or points adjacent to the burnerscould equally well be utilized.

Although drain line 38 could, of course, be connected to a sewer, etc.,by utilizing the reservoir tank 40, the highly purified water utilizedin the steam-generator is not lost and can be returned to thesteam-generator when operation is restored.

As can be seen from FIGURE 1, the steam-water portion of the system isof the closed circuit type and comprises steam lines 18 and 20, turbine22, turbine exhaust line 43, condenser 44, line 47, feed pump 16, andfeedwater line 14 connected back to the steam-generator. The circuit ishermetically sealed so as to eliminate the necessity of supplyingmake-up water. This is important, especially in units designed forresidential use, since the addition of a make-up water system wouldunduly complicate the unit.

Steam condenser 44 could be of many types; however, as shown, itcomprises a conventional heat exchange coil over which air is conductedby a fan 46. Fan 46 and condenser 44 are positioned in a duct 48, theends of which are connected to outside air.

Reversible refrigeration cycle system B Although a variety of differentheat pump systems could be used, system B is a conventional reversiblerefrigeration cycle comprising an outside heat exchanger 50 and aninside heat exchanger 52 connected with each other through aconventional expansion valve 55, and through a two-position four-waymode valve 54 with compressor 56 of the turbo-compressor unit C.

Mode valve 54 eontitutes means for permitting the heat exchangers 50, 52to selectively function as either the evaporator or condenser. In thismanner inside heat exchanger 52 can perform as either a heating orcooling coil.

Heat exchanger 50 is positioned in a duct 58 which is communicated withthe exterior of the building through an inlet duct '60 and an outletduct 62. An electric motor driven fan 64 is provided to assure thenecessary air flow across the heat exchanger.

A similar duct system is provided for heat exchanger 52, and includes aduct 66 communicated with the interior of the building through a returnair duct 68, and a supply air duct 70. An electric motor driven fan 72provides air circulation through the interior of the building and acrossheat exchanger 52.

Although no controls are shown for fans 46, 64 and 72 they would, ofcourse, be provided with means to assure their operation during theperiods when thermostat 36 is indicating a need for heating or cooling.The particular controls used for this purpose are not important to thepresent invention and could, for example, be merely switches operated bya solenoid or solenoids energized through thermostat 36.

H eating mode operation An important feature of the present invention isthe arrangement provided for heating mode operation. During the periodswhen heating is required in the building, mode valve 54 will, of course,be shifted so that heat exchanger 52 is functioning as the condensercoil and the heat extracted therefrom is supplied to the building.Additionally, substantial heat is also available from condenser 44 ofthe steam-water cycle portion of the overall system. For this reason apair of connecting duct means 74, 76 are provided between ducts 48 and66. Flow of air through these ducts is controlled by means in the formof four dampers 78, 80, 82 and 84 positioned at the junctions of theducts.

During cooling operation the dampers would be in the position shown bysolid lines; however, when the system is shifted to heating operationthe dampers are moved to the positions shown by dotted lines. With t.edampers in these positions, the air coming through return air duct 68 ispassed first through heat exchanger 42, then via duct 74 to duct 48 andacross condenser 44. The air is then conducted through duct 76 back toduct 66, and then to the building air supply duct 70. In this manner,heat in condenser 44, which would otherwise be lost to the outsideatmosphere, is utilized to heat the building air and the overallelficiency of the system substantially improved.

The means used to move the dampers between their heating mode andcooling mode positions could be of a variety of forms, either manual orautomatic. For example, the dampers could be provided with a mechanicalinterconnection with mode valve 54 so that when the valve is shiftedfrom heating to cooling operation the dampers would be simultaneouslyshifted.

Because during extremely cold weather, the above described arrangementmay not be adequate to supply sufficient heat at the necessarytemperature ratio, means are provided to increase the amount of heatavailable at condenser 44. These means comprise a line 86 which extendsbetween steam line 18 and the inlet to condenser 44 and by-passesturbine 22.

A valve 88 is provided to control the flow of steam through line 86. Thevalve could be of a variety of types either manual or automatic, but isshown as of the pressure-opening type to respond to increased systemoperating pressure. The increase in system pressure is achieved throughuse of the two-step thermostat 36, which modifies the set point ofpressure control valve 32 when room temperature is a predeterminedamount below the thermostat set point.

As can be seen, the above-described damper and steam by-pass arrangementprovides the system with a high degree of flexibility and greatlyincreases its overall efliciency.

Turbo-compressor unit C As shown in FIGURE 2, the turbo-compressor unitC comprises a compressor 56 which is drivingly connected through aspecially designed magnetic coupling 100 with vapor turbine 22. A feedpump 16 is carried on the lower end of the turbine shaft.

All of the various components are mounted in a housing indicated ingeneral by the numeral 90. Housing 90 could take many forms and beconstructed in a variety of ways; however, as shown it comprisescylindrical drum 91 having its upper end sealed by plate 91a which isclamped to the drum by a circumferentially extending clamp ring 91b. Apartition forming member 92 divides the interior of the housing intofirst and second sealed chambers. A pair of transversely extendingsupports 94 and 96 are rigidly supported in spaced relation in the lowerof the chambers by the rods and sleeves 95a. A plurality of largeO-rings 97 are provided to mechanically isolate and seal the varioussupport and partition members from the drum and to transfer the Weightof the components to the drum at ring 910.

Compressor 5 6 The exact construction of compressor 56 is not importantto the present invention. However, according to the preferred embodimentit comprises a relatively conventional two stage supersonic typecompressor. As shown it comprises a main housing assembly 101 whichcarries a vertically extending shaft 120 rotatably mounted on a pair ofbearing assemblies 130 and 130 and carrying the impellers 104 and 104'.The compressor assembly is rigidly tied to the partition plate 92 by aplurality of bolts 93.

Because both stages of the compressor are substantially identical onlythe first stage will be described in detail and the corresponding partsof the second stage will be identified by the same reference numeralswith the addition of a prime suflix. A description of one part is to beconsidered equally applicable to the corresponding part unless otherwisenoted.

The first stage of the compressor comprises a housing section 101aprovided with scroll shaped ditfuser-collector section 102 and impeller104. The fluid to be compressed is supplied to the impeller 104 fromline 106 through inlet 108. Inlet 108 is sealed where it passes throughplate 910! by a flexible seal 108a.

The compressed fluid exiting from the diffuser-collector section 102 isconducted from outlet 109 to the inlet section 110 of the second stageby lines 110a. The connection between outlet 109 and inlet section 110is not shown but comprises a simple T or Y fitting and the necessaryconnecting lines. The outlet 111 from the second stage passes in sealedrelationship through the container 91 into connection with line 112 (seeFIGURE 1).

As previously mentioned, bearing assemblies 130 and 130' support shaftfor free rotation in housing assembly 101. In general these assembliesare substantially identical with the exception that assembly serves asthe thrust bearing and supplies the vertical support for the shaft 120.

As shown, bearing assembly 130 includes a plurality of annular shapedhousing members 132, 134 and 136. These members are joined together withsections 101a and 101a and the corresponding lower housing sections 132,134' and 136', by vertically extending bolts not shown. Positionedwithin the housing thus formed, and carried by circumferentiallyextending O-rings 144 is a carbon bearing forming member 146. Bearingforming member 146 is of annular configuration, and is provided with aplurality of radially extending passages 150 for supplying lubricantfrom lines 152 to the bearing surface between shaft 120 and the bearingforming members. Member 146 also is provided with a vertically extendingpassage 154 adapted to supply lubricant to the bearing surface betweenit and thrust washer 124. A drain line 156 serves to carry away thelubricant.

The lower surface of member 136' of bearing assembly 130' is connectedto the radially extending flange 160 of the barrier member 186 ofmagnetic coupling 100 which is in turn connected to, and supported by,internal support member 92. The joints between these connections aresealed by O-rings 164 and 166.

Magnetic coupling 100 As previously discussed, past attempts to design avapor turbine driven refrigerant compressor unit of small size have beenlargely unsuccessful because of the incompatibility of the mostdesirable fluids for use in the refrigerant cycle and the vapor turbinecycle, and the inability to adequately seal between the two fluids.

The present device overcomes this problem by providing a magneticcoupling between the turbine and compressor in a manner which eliminatesthe need for mechanical seals. Because of the necessary high rotativespeeds of the turbine (in the range of 50,000 r.p.ms and higher), andthe consequent high centrifugal forces imposed on the magnetic coupling,a coupling of special design is utilized.

As shown in FIGURE 2, this coupling comprises a cylindrically shapedinner magnet assembly 180 carried on the lower end of shaft 120, and inouter magnet assembly 182, of cup shaped cylindrical configuration,carried on the upper end of the turbine shaft 184. A cup-shaped barriermember 186, formed from an impervious nonmagnetic dielectric material,such as Pyrex glass, is positioned between the inner and outer magnetsand connected in sealing relation at its flanged end 160 to support 92.

Inner magnet assembly 130 comprises a plurality of individual magnetdiscs 188 formed from Alnico and 3 snugly fitted to the lower end ofshaft 120 and positively connected thereto by a nut 190.

The outer magnet assembly 182 includes a hub member cast integrallywith, or shrink-fitted to the turbine shaft. Positioned immediatelyabove hub member 192 is outer magnet member 195. As best shown in FIGURE3, the outer magnet member includes a plurality of vertically extendingmagnet poles formed in a body 1% of Alnico.

Outer sleeve 204 provides the main structural strength for the assemblyand is formed from fiber glass and resin. The main portion of the fibersis circumferentially wound because of the large circumferential loadgenerated during rotation. The sleeve 204 is shrink fitted to the outermagnet member, preferably by hydraulically expanding it by positioningthe sleeve vertically between a pair of end plates which close the endof the sleeve and are held in position by a clamp or tie rods. Thispermits the sleeve to sealingly retain hydraulic fluid. The top endplate is provided with a recess which receives the magnet member andpermits it to rest on the top edge of the sleeve while the sleeve is inthe unexpanded condition. Consequent pressurization of the hydraulicfluid by a pump communicated with the fluid in the sleeve through a linein one of the end plates, causes the sleeve to be expanded and themagnet member to drop into position in the sleeve.

When constructed in the above-described manner, the magnetic coupling iscapable of transmitting the necessary torque from turbine 22 tocompressor 56 at rotational speeds substantially above 50,000 r.p.m.

Vapor turbine 22 Vapor turbine 22 is similar to the conventional Terrytype turbine, and includes a rotor 220 shrink fitted or otherwisepositively connected to shaft 184. The outer periphery of the rotor isprovided with a plurality of fins or blades (not shown) which aresupplied with steam from line 20 by nozzle 222. A shroud 226 ispositioned around the rotor.

The rotor is mounted for rotation by an upper bearing assembly 228 and alower bearing assembly 230. These bearing assemblies are constructed inbasically the same manner as previously described bearing assembly 130.

In particular, upper bearing assembly 228, includes an annular shapedbearing housing member 232 and a pair of inwardly extending bearingsupport members 234. A pair of O-rings 236 serve to support the carbonbearing 238 on support members 234. Radially extending lubricationpassages are provided in bearing 238 and function to provide lubricantfrom line 240 to the bearing surface between shaft 184 and bearing 238.

Positioned immediately below the bearing assembly 228 and connectedthereto is a circumferentially extending bearing lubricant receivingmember 242 provided with drain line 244. Normally steam or feedwaterwill serve as the bearing lubricant for the turbine bearings. In thecase of feedwater, the drain line 244 is connected with line 47, andlubricating fluid returned to the system.

Lower bearing assembly 230 serves to provide the main support for theturbine and for this reason includes a thrust washer 246 carried on acarbon bearing member 248 which is mounted between a pair of O-rings 249carried by a pair of radially extending support rings 250 positioned onopposite sides of bearing housing forming member 252. The bearinghousing member 252 is connected to the underside of support member 96 inany manner which will properly support the weight of the turbine andseal the turbine chamber.

Bearing lubricant in the form of feedwater or steam is supplied to thebearing surfaces of bearing 248 from line 254 and passages 256. Noseparate bearing lubricant drain line is provided for bearing assembly230, since the hearing is in direct communication with hot-well 260which is connected in sealed relation with the bearing support.

Feed pump 16 Of particular importance to the present invention is theconstruction of feed pump 16. As previously mentioned because of thehigh vacuum conditions under which the turbine operates, and the smallstatic fluid head available in a small system like the present,conventional small centrifugal and piston pumps do not functionproperly. In general, when attempting to operate conventional pumps ofthe smaller sizes under the conditions present in the subject system,priming difficulties, as well as vapor binding, are experienced. Forthese reasons, the present invention includes a specially designed feedpump.

In general, the pump could be referred to as an inverted cone,surface-action pump. In particular the pump includes a generallyconically shaped member 270 formed on the lower end of turbine shaft 184which extends into a fluid container means in the form of a hot-well260. Although, shown as a cone, the exact shape of the member could varyslightly and could for example, be of semielliptical cross-sectionalconfiguration. Positioned immediately above the end portion 270 andfirmly connected to shaft 184, such as by welding or shrink flitting, isa disc shaped fluid receiving member 272 having a circular recess 274 inits lower side. A member 276 is connected to the lower side of member272 and in combination with recess 274 provides a circumferentiallyextending inwardly opening fluid receiving channel means. A fluidreceiving means shown as a stationary pick-up tube 278 extends into thechannel and has an open end 280 facing opposite the direction ofrotation of shaft 184. The other end of tube 278 is connected withfeedwater supply line 14 through a connection carried in bearing housingforming member 252.

Obviously the most efiicient angle for the conically shaped member 27 0will vary depending upon factors such as the speed of rotation, thecharacteristics of the fluid, etc. In the present application, withwater near its boiling point, and with the pump rotating in the range of40,000 to 70,000 r.p.m. an angle of from 20 to 40 is satisfactory.

The operation of the pump can best be explained by reference to FIGURE4. All that is required to initiate pumping action is rotation of thecone when its end is submerged in the liquid. As shown, when the end ofthe cone is submerged in the liquid, the liquid rises a short distanceup the cone in a meniscus-like fashion at 280.

As the cone is rotated, the forces acting on the liquid mass include acentrifugal force indicated by vector D, and a gravitational forceindicated by vector E. These forces are counteracted by a force whichresults from the surface tension of the liquid and is indicated byvector C. Vector C, is, of course, comprised of an axial componentindicated by vector A, and a radial component indicated by vector B.

The centrifugal force D increases with film thickness, whereas theresultant surface tension force C does not. Therefore, for a giventangential velocity on the cones surface, there is an equilibrium filmthickness, at which the radially inward component B of the surface forcebalances the centrifugal force D. The remainder of the surface forcevector revolves axially, toward the large end of the cone, which forsteady state fiow will be balanced by the force of gravity.

As can be seen, the equilibrium film thickness reduces as the conediameter increases. This is also a requirement for flow continuity forsteady velocity up the cone. Any voids on the cone surface will thenoccur at the upper end of the cone, which will increase the liftingforce on the fluid, drawing it into the void. Any vapor which forms as aresult of heating caused by fluid slip on the cone surface will beejected from the film since surface forces on a vapor are minimalcompared to those on the liquid.

As the liquid moves up the cone it is accelerated tangentially becauseof drag between it and the cones surface. Since there is slip betweenthe cone surface and the liquid, the liquid will have a tangentialvelocity with respect to the cone surface. This tends to keep a uniformfilm thickness around the cone at any given axial level. As the liquidreaches the receiving channel 276, the tangential velocity (or dynamichead) possessed by the liquid is recovered as pressure via a rapiddiffusion process in the impact tube or collector tube 278.

As is apparent, the advantages of the above-described pump are numerousand include its extreme simplicity and freedom from seals, as well asits immunity from cavitation problems even when functioning in a vacuumenvironment within one millimeter of mercury from the liquids vaporpressure. Additionally, the pump is selfpriming under the same vacuumconditions and is ideal for the low flow-high head operation required inthe subject system.

As can be seen from the foregoing specification, a fuelfired reversecycle heat pump system has been provided which is highly simple inconstruction and operation, and overcomes the problems previouslyencountered in such systems.

The invention has been described in great detail sufficient to enableone of ordinary skill in the heating and cooling art to construct anduse the same. Obviously modifications and alterations of the preferredembodiment will occur to others upon a reading and understanding of thespecification, and it is our intention to include all such modificationsand alterations as part of our invention insofar as they come within thescope of the appended claims.

Having thus described our invention, we claim:

1. A vapor turbine driven heat pump system comprising: a closed vaporcycle including a vapor cycle generator means supplying vapor from saidvapor generator to said turbine, a first heat exchanger for receivingand condensing said vapor after it has passed through said turbine, pumpmeans for returning said condensed vapor to said vapor generator; aclosed-circuit reversible refrigerant cycle including a compressor andmeans drivingly connecting said compressor to said turbine, a secondheat exchange and means to selectively cause said second heat exchangerto function as the condenser or evaporator for said refrigerant cycle;air duct means interconnecting said first and second heat exchangers,and means for causing air to flow through said duct means first oversaid second heat exchanger and thence over said first heat exchangerwhen said second heat exchanger is functioning as a condenser.

2. The system as defined in claim 1 wherein a bypass line means isprovided for bypassing said turbine to permit vapor to be conducteddirectly from said vapor generator to said first heat exchanger.

3. The system as defined in claim 2 including a valve in said bypassline means.

4. A system as defined in claim 1 wherein said pump means includes: acontainer means for receiving said condensed vapor, an elongated memberhaving a longitudinal axis and extending downwardly into said containermeans, said member having a lower end adapted to extend into thecondensed vapor in said container and having a circular cross-sectionalconfiguration as defined by planes perpendicular to said longitudinalaxis which gradually increases upwardly from said lower end, meansdefining a circumferentially extending fluid receiving recess upwardlyspaced from said lower end, fiuid pick-up means positioned within saidrecess for receiving liquid received therein.

5. A system as defined in claim 4 wherein said turbine has an outputshaft rotatable about a longitudinal axis and said elongated member iscarried by said output shaft in axially aligned relationship.

References Cited UNITED STATES PATENTS 2,219,815 10/1940 Jones 62-238 X2,952,138 9/1960 Russell 62-238 3,153,442 10/ 1964 Silvern 62-467 X3,194,026 7/1965 La Fleur 62-88 3,196,631 7/ 1965 Holland 62-238 WILLIAMJ. WYE, Primary Examiner.

